The marine industry implements a wide variety of systems directed to controlling the growth of barnacles on marine surfaces, including the use of bottom paints, electrodes, and ultrasonic systems. Each of these systems and methods has specific advantages and disadvantages.
Patent Publication No. PCT/AU2005/001676 describes a method to introduce swept ultra-sound waves into a marine surface in order to form waves of compression and expansion, thereby creating microscopic bubbles. These bubbles collapse quickly causing a high temperature which breaks down the shell of most organisms. However, implementing such a system to remove barnacles across a hull is not a simple or energy efficient method.
U.S. Pat. No. 5,735,226 describes an array of transducers generating an ultrasonic signal. This is swept and received to enhance the ultrasonic energy generated. The array of transducers is placed on the hull to inhibit the growth. This is expensive and difficult to overcome the structural configuration impact on ultrasonic energy. U.S. Pat. No. 4,058,075, entitled “Marine Life Growth Inhibitor Device”, describes an acoustical vibration device in which a plurality of speakers located around the inside of the boat hull is used to inhibit the growth of marine life. The larger and more dense the vessel, the more difficult this would be to implement. U.S. Pat. No. 3,650,924 proposes heating the bottom of the vessel to inhibit growth. This would not be practical due to the amount of energy required.
U.S. Pat. Nos. 3,661,742 and 3,650,924 describe methods to inhibit the attachment of marine organisms through cathodic protection. Toxic ions are forced into solution in the seawater used to cool or contain the vessel. There are many systems implemented in this fashion but none are simple to implement within the vessel interior spaces. U.S. Pat. No. 3,837,916 proposes spraying fresh water to prevent attachment of marine microorganisms. This is not practical, as the source of fresh water in a salt water environment is limited.
U.S. Pat. Nos. 5,308,505 and 5,322,569 describe an ultraviolet light system which irradiates the water underneath the vessel and adjusts the intensity to kill barnacle larvae to prevent their attachment to the underwater surface. Another implantation of this system shows that the water is passed through a biocidal chamber with UV light of specific intensity for at least one minute exposure time. These patents do not describe or implement a system that fits within existing marine systems.
Commercially available systems include: i) Shanghai Cyeco Environmental Technology Marine Growth Preventing System, which makes an electrode based system; ii) Cathelco Limited, which makes electrode protection system; iii) UltraSonic Antifouling, Ltd., which makes an ultrasonic systems; and iv) Spectra Watermakers, which makes a passive copper anode system.
Therefore, there is a need for improved systems for controlling barnacle formation and growth in marine environments.